Liner plate junction seal

ABSTRACT

The interengagement of adjacent liner plates in blasting machines is provided with a volumetrically-resilient seal, the seal being of a material capable of absorbing the energies of particles entering the junction at high velocity.

51/9 Bowling 51 Apr. 2, 1974 3,191,346 6/1965 2,732,666 1/1956 Powell 3,660,943 5/1972 Barnthouse.. 3,319,383 5/1967 51/9 Primary ExaminerDonald G. Kelly Attorney, Agent, or Firm-Glenn B. Morse [57] ABSTRACT The interengagement of adjacent liner plates in blasting machines is provided with a volumetricallyresilient seal, the seal being of a material capable of absorbing the energies of particles entering the junction at high velocity.

6 Claims, 8 DrawingFigures Barnes LINER PLATE JUNCTION SEAL Grand Rapids, Mich. 49504; Bernard Fuerst, 804 Conger, N.E., Grand Rapids, Mich. 49505 Filed: June 26, 1972' [21] Appl. No.: 266,472

Int. Field of References Cited UNITED STATES PATENTS [76] Inventors: Joseph R. Sack, 1721 Sandra, N.W.,

0 m U N 5 United States Patent Sack et a1.

PATENTEB APR 2 I914 SHEEI 1 BF 3 PATENIEDAPR 219:4 3.800.474

SHEET 2 0? 3 LINER PLATE JUNCTION SEAL BACKGROUND OF THE INVENTION The term blasting machine refers to a conventional 7 piece of industrial equipment adapted to project a stream of abrasive particles at extremely high velocities. The stream is directed at the surface of pieces being processed, either to clean them or to generate particular surface characteristics. The most common of these machines includes a rotor driven at high speed, this rotor having the general configuration of a paddle wheel. Abrasive particles are fed into the central area of this wheel, and the peripheral velocity of the wheel is imparted to the particles to produce a tangential stream. Interengagement of the particles with the various surfaces on the'machine tends to produce the same effect there as on the work pieces toward which the stream is projected. The surfaces exposed to the stream are therefore normally lined with plates of extremely hard cast material, and these plates are secured to or suspended from a housing structure which the plates are designed to protect. The plates are expendable, and are replaced periodically.

The hardness of the plates is such that they are machinable only by relatively expensive grinding operations, which are avoided wherever possible in the interest of economy. The interengaging surfaces of the plates are frequently in a tongue-and-groove configuration to minimize the possibility of particle leakage and consequent damage to the housing. The result of leaving the interengaging surfaces in the as-cast condition is to inevitably produce sections of substantial length where the plates are not in mutual contact, producing clearance areas permitting the escape of particles at high velocity. The particles are relatively free to travel along these passages and erode the surfaces of the liner plates which define these passages. The problem is particularly acute in the areas where the liner plates join near the rotor periphery, since the tangential velocities of the patticles are frequently closely parallel to the junctions of the liner plates in this area. The liner plates are frequently quite thick, except at portions of the tongue-and-groove interengagement, and wear at the base of the groove (for example) can destroy a liner plate long before its useful life would normally terminate. This area of erosion is not readily visible to inspection without removal of the plates, with the result that the'plates can break through and permit the progressive destruction of the housing without much warning.

SUMMARY OF THE INVENTION The present invention provides a volumetrically compressible seal placed at the interengagement between adjacent liner plates so that the spaces between the plates at the junction are solidly filled. In the preferred form of the invention, the sealing material is in the form of a strip of foamed synthetic of a texture and resiliency similar to foam rubber, and is selected from materials which retain their resilience in the presence of lubricants or the particular environment in which the machine is to be operating. The sealing material is preferably incorporated in the form of a strip having larger cross sectional dimensions-than those of a groove in which it is installed, with the face of the strip engaging the base of the groove being provided with an adhesive.

Particles entering the groove at high velocity will have the velocity energy quickly dissipated by interengagement with the resilient cellular structure of the sealing material, which can be torn and damaged locally to a very considerable extent without interference with its function. In addition to the sealing characteristics, the presence of the resilient seal material provides a desirable cushioning effect for the transfer stresses associated with mounting or vibration, thus tending to inhibit cracking and reducing noise level.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view, partially in section, of a conventional blasting machine modified to incorporate the sealing arrangement provided by the present invention.

FIG. 2 is a fragmentary section in perspective, on an enlarged scale over that of FIG. 1, illustrating the sealing arrangement at the junction of the liner plates. 7

FIG. 3 is a fragmentary axial section (with respect to the rotor axis) on an enlarged scale over that of FIG. 2, and showing the liner plate junction provided with the seal.

FIG. 4 is a fragmentary section in perspective of a different configuration at the junction of adjacent liner plates from that of FIG. 2.

FIG. 5 is an axial section on an enlarged scale over that of FIG. 4, illustrating the sealing arrangement.

FIG. 6 is aperspective view of a piece of the preferred form of the sealing material.

FIG. 7 is a section on a plane normal to the axis of the machine, illustrating a conventional arrangement for supporting liner plates. The rotor assembly is re moved.

FIG. 8 is a section on a plane 8-8 of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The machine illustrated in FIGS. 1, 2, and 3 includes a base frame 10 carrying appropriate bearings, such as those shown at 11, supporting the shaft 12 of the rotor assembly 13. The shaft 12 has a multiple-groove sheave 14 adapted to receive a series of V-belts for the transmission of power. The rotor includes the axiallyspaced plates 15 and 16 and a group of radially oriented blades as shown at 17 arranged in evenly spaced sectors about the axis of the shaft 12.

A housing for the rotor assembly 13 includes the front and back panels 18 and 19, respectively, a removable top panel 20, and the side panels 21 and 22 (refer to FIG. 7). The front panel 18 is interrupted to provide for the feed supply assembly generally indicated at 23, which conducts abrasive particles into the central area of the rotor, from which-the particles are accelerated by the rotating blades to produce a tangential stream emerging from the bottom of the assembly, as viewed in FIG. 1.

To protect the interior of the housing, it is lined with a material of extreme hardness. This lining is broken up into a series of interengagedplates secured by either positive attachments or by clamping devices on the housing. The front and back panels of the housing are lined by an assembly of three plates each, of a configuration similar to that shown in FIG. 7. The plates 24,

25, and 26 each occupy a sector of approximately and may have cast-in nuts or other securing points positioned as indicated at 27-38. These points will normally be interengaged with bolts or screws traversing the housing.

When the opposite front and rear liners are mounted in a relationship indicated in FIG. 7, these become available as a support for the peripheral liner plates 39, 40, and 41. The plates 39 and 41 are laid against the side of the assembly of front and rear plates, and are clamped in this position by the screws 42 and 43, carried in the bosses 44 and 45 respectively of the housing panels 21 and 22. The top liner 40 is laid in place over the upper portion of the assembly, and is clamped in position by the clamping screws 45 and 46 in threaded engagement with the portions 47 and 48 respectively, of the side panels 21 and 22. The cover of the housing is held in place by the bolts 49 and 50 pivotally secured to the portions 51 and 52 of the sides 21 and 22 of the housing, and secured by the nuts 53 and 54. All of these plate components are of substantial thickness in the central area to provide the desirable wear characteristics, and the hardness of material prevents, as a practical matter, machining the interengaging surfaces to the point of producing a particularly close fit.

This invention is particularly concerned with the sealing of the interengaging edges of the various liner plate segments. Typical of this is the junction of the rear and front plates with the top and side plates. Typical of this is the showing at FIG. 2, which illustrates the junction between the top plate 40, the front plate 55, and the rear plate 24. It is conventional to provide a tongue-and-groove interengagement between the plates at this junction, but experience has shown that this is not at all adequate to prevent the high-velocity abrasive particles from finding their way into the small passages provided by the looseness of interengagement in these areas. Once this flow of abrasive particles begins to develop, it rapidly erodes the material to the point of destruction of the components. The tongue 56 on the top rear plate 24, for example, will never quite fill the corresponding groove in the top plate 40, both with regard to radial depth and axial width (with respect to the axis of the rotor assembly 13). These areas of clearance thus form inviting channels for the passage of abrasive particles, which have worked their way into the area indicated at 57 in FIG. 3. While substantial thickness of material is present at this point, the thickness of the top plate 40 in the area indicated at 58 is relatively thin, and subject to rapid erosion to the point where fracture can easily occur. This problem can be eliminated by the insertion of the sealing strip 59 of a foamed resilient material such as rubber, or polyurethane of comparable resilience, in the groove engaged by the tongue 56 and in other comparable positions throughout the machine. The strip 59 preferably is initially somewhat wider than the groove in which it is inserted, and a layer of adhesive 60 secures the strip to the base of its groove. The initial uncompressed thickness of the strip 59 is preferably a thickness which occupies at least a major portion of the depth of the groove. The insertion of the tongue into the groove will thus result in the strip 59 being compressed and forceably urged laterally into solid engagement with the axially opposite sides of the groove, and fully occupy all of the space between the outer extremity of the tongue and the base of the groove. All of the space available as a channel for the passage of abrasive particles is thus blocked. It is important that this blockage is performed by a material which is capable of resiliently absorbing the velocity energy of the abrasive particles, and it should also be noted that the foamed cellular structure of the strip 59 will withstand a tremendous amount of abuse from the abrasive particles without degenerating to the point where it is no longer able to absorb the velocity energy. It will therefore retain its ability to slow down the particles to the point that they cannot damage the surrounding metal components. The compressibility of the sponge-like material continually tends to urge new portions of it into the path of the oncoming particles as the material may be eroded or otherwise consumed.

Referring to FIGS. 4 and 5, a modified plate configuration is shown in which the front and rear plates 61 and 62 do not have tongue-and-groove interengagement with the top plate 63 at the grooves occupied by the sealing strips. The strips 64 and 65 are in engagement with the peripheral surfaces 66 and 67, respectively, on the plates 61 and 62. These peripheral surfaces are received in offsets on the top plate 63, and the offset surfaces are provided with the grooves for receiving the sealing strips, as shown in FIG. 5. Each of the strips 64 and 65 is provided with an adhesive layer as shown at 68 and 69 to hold it in engagement with the associated grooves. The assembly of the plates is easier if attention does not need to be given to holding the seal strips in place as the plate edges are interengaged. The presence of the strip 64 between the peripheral surface 66 and the offset surface 70 not only seals the gap between the surfaces, but provides a mass of resilient material that will degrade the velocity of any particles entering into the area indicated at 71 in F IG. 5, and which might retain sufficient energy to ricochet back and forth between the surfaces immediately to the right of the strip 64 shown in FIG. 5.

We claim:

1. A blasting machine having a housing, means operative to produce a high velocity stream of abrasive particles within and projecting from said housing, a plurality of cast liner plates adapted to cover at least portions of the interior of said housing, certain of said liner plates having an overlapping bearing engagement along a first surface of at least one offset in said certain liner plates, said first surface extending from an interior surface of said certain liner plates, said offset being at least in part defined by a second surface intersecting said first surface along a portion interengaged with an adjacent liner plate, and means securing said liner plates with respect to said housing, wherein the improvement comprises:

a strip of resilient deformable material disposed against said second surface and interposed between said second surface and the liner plate adjacent thereto said material having a free thickness prior to interengagement of said plates selected to occupy under compression all of the space between said second surface and said adjacent liner plate on assembly of said plates to said housing.

2. A blasting machine having a housing, means operative to produce a high velocity stream of abrasive particles within and projecting from said housing, a plurality of cast liner plates adapted to cover at least portions of the interior of said housing, certain of said liner plates being interengaged in tongue-and-groove relationship along a path substantially parallel to said stream, and means securing said liner plates with respect to said housing, said means being operative to LII cluding adhesive material interposed between said strip and the bottom of said groove.

4. A machine as defined in claim 2, wherein said strip is composed substantially of gas cells.

5. A machine as defined in claim 2, wherein the free width of said strip exceeds the width of said groove 6. A machine as defined in claim 2, wherein the said strip, on insertion thereof into said groove and prior to the interengagement of said plates, substantially fully occupies said groove. 

1. A blasting machine having a housing, means operative to produce a high velocity stream of abrasive particles within and projecting from said housing, a plurality of cast liner plates adapted to cover at least portions of the interior of said housing, certain of said liner plates having an overlapping bearing engagement along a first surface of at least one offset in said certain liner plates, said first surface extending from an interior surface of said certain liner plates, said offset being at least in part defined by a second surface intersecting said first surface along a portion interengaged with an adjacent liner plate, and means securing said liner plates with respect to said housing, wherein the improvement comprises: a strip of resilient deformable material disposed against said second surface and interposed between said second surface and the liner plate adjacent thereto said material having a free thickness prior to interengagement of said plates selected to occupy under compression all of the space between said second surface and said adjacent liner plate on assembly of said plates to said housing.
 2. A blasting machine having a housing, means operative to produce a high velocity stream of abrasive particles within and projecting from said housing, a plurality of cast liner plates adapted to cover at least portions of the interior of said housing, certain of said liner plates being interengaged in tongue-and-groove relationship along a path substantially parallel to said stream, and means securing said liner plates with respect to said housing, said means being operative to press said interengaged liner plates together in a direction to increase the depth of said interengagement, wherein the improvement comprises: a strip of resilient deformable material disposed in said groove and interposed between the bottom of said groove and said tongue, said material having a free thickness prior to interengagement of said plates, in the direction of the depth of said groove, selected to occupy under compression all of the space between said groove bottom and said tongue on assembly of said plates to said housing.
 3. A machine as defined in claim 2, additionally including adhesive material interposed between said strip and the bottom of said groove.
 4. A machine as defined in claim 2, wherein said strip is composed substantially of gas cells.
 5. A machine as defined in claim 2, wherein the free width of said strip exceeds the width of said groove.
 6. A machine as defined in claim 2, wherein the said strip, on insertion thereof into said groove and prior to the interengagement of said plates, substantially fully occupies said groove. 